Motoped style delta trike

Discussion in 'Motorized Trikes' started by SimpleSimon, Oct 23, 2010.

  1. SimpleSimon

    SimpleSimon Active Member

    The discussion a couple three weeks back about the motoped type design got me to thinking, and I sketched up a quick basic frame design. Looking at that got my minds eye to seeing stuff that ain't there (not a hallucination, however), so I decided to play with the design just a bit.

    How about an independent rear suspension delta trike based on that idea? As I've drawn it, it has 24 x 2.125" wheels all around, with independent swing-arm rear suspension, and a twin shock 4" travel front suspension fork. Wheelbase is 51 9/16" long x 30" wide.

    Attached Files:

  2. Tikihead

    Tikihead New Member

    Hey SimpleSimon,

    These are great drawings! How do you see a motor being attached?
  3. SimpleSimon

    SimpleSimon Active Member

    Attached is a closer, more detailed view, showing the vertical and horizontal clearances from the pedal crank. Any kind of mounting system you'd like can be done.

    Personally, I see it with an HT 2 stroke, running through a jackshaft to a secondary crank ring, then a 5 speed rear hub used as a mid-drive, with spoke-flange mounted drive sprocket and chain loops back to the half-axle free wheel capable sprockets.

    Attached Files:

  4. happycheapskate

    happycheapskate Active Member

    I like the idea, but how will you reconcile the two independant arms and the drive system?

    Why not make a live-axle and mono-shock rear with limited flex/lean capability? That would still be difficult, but probably more simple overall.

    If you really like the design in the original post, you could set up pedal system to one rear wheel, and run a rack-drive/friction drive on the front wheel. That would work and still use disc brakes if you want.
  5. SimpleSimon

    SimpleSimon Active Member

    Happy, what I've posted here is a bare frame design. I am in the process of doing a "fully dressed" model incorporating an HT engine, jackshaft, secondary (freewheel) crank chain ring, shimano five speed rear hub as the mid-drive, and separate chain loops from that to the final drive sprockets on the inner ends of each half-axle. Each rear suspension swing arm will support spring mounted chain tension adjusters in those final loops.

    This will result in a fully functional five speed independent suspension delta trike with both power loops (pedal and engine) driving the mid-drive, with the freewheel capable rear half-axle sprockets permitting a differential effect, and power at both rear wheels.

    Once I complete that model, I'll post pics of it from various angles, and some close ups to show details.
    Last edited: Feb 7, 2011
  6. happycheapskate

    happycheapskate Active Member

    It will probably weigh a lot, but it will look cool.
  7. Alaskavan

    Alaskavan Guest

    Keep us posted on this one. I have most of the pieces for a similar build sitting around here. Just haven't had the time to work on it.
  8. SimpleSimon

    SimpleSimon Active Member

    My trike conversion weighed in at 42.5 pounds, fully dressed. About 8 pounds of which was mostly cosmetics (engine skirting, extended rear rack, fabricated Tonka Truk style fenders on the rear).

    This one can be done for around 50 pounds, probably less. Not something you'd want to pedal home in hilly terrain, but still manageable.
  9. professor

    professor Active Member

    Interesting design, very origional, but the loading on the back will cause the suspension members to twist. Lots of load on the pivot points of those triangles too.

    Two bars across the back linking them together with pivoting ends (Forget what they are called - maybe Watts type links) could take the twisting load off the triangles.

    Down from the steering head- big load point.
    You need much bigger tubing going down or an added member down to the lower portion of the seat post.
    Not being critical. don't want to hear of you getting hurt.
  10. SimpleSimon

    SimpleSimon Active Member

    Valid points on that rear suspension, which is part of why the contemplated weight is expected to be fairly high - the pivot axis is designed around a 3/4 inch cold-rolled hi-moly steel shaft. I have contemplated adding a rear torsion bar anti-twist reinforcing shaft as well, limited flex coupled at each end.

    The head tube as designed is more than strong enough for the calculated loads, as is the joint to the backbone member. The design is a pretty straightforward adaptation of a motoped style dirt bike frame, and the predicted loads that type frame will sustain are MUCH higher.

    Suspension or not, it remains a delta trike, and it will display some if not all of the limitations of that type design. Mostly, the operating CoG is still high, with the resultant inertial moment arms in turning being only partially offset by the suspension.

    Actually, I am also working on a derivative design which has a lower CoG, shorter suspension arms, and more of a crank-forward type frame.